Neutral switch system for transmission

Abstract

A vehicle transmission includes a plurality of shift shafts that cooperate with a common neutral switch to control when range shifts occur. In one example, the plurality of shift shafts includes a first shift shaft, a second shift shaft, and a third shift shaft that is positioned between the first and second shift shafts. A plunger actuates the neutral switch in response to movement of the third shift shaft along an axis. A first switch pin is positioned between the first shift shaft and the plunger and a second switch pin is positioned between the second shift shaft and the plunger. The first and second switch pins move the plunger to actuate the neutral switch in response to axial movement of a respective one of the first and second shift shafts. Thus, each of the first, second, and third shifts shafts can actuate a single neutral switch by cooperating with a common plunger.

1. A vehicle transmission comprising:
 a transmission housing; 
 a plurality of shift shafts disposed within said transmission housing with each shift shaft being movable along an axis; 
 a plunger adapted for independent actuation by each of said plurality of shift shafts, said plunger comprising a single-piece component having an enlarged head portion that directly transitions into a reduced body portion; and 
 a neutral switch aligned with said enlarged head portion, said neutral switch being received within a neutral switch bore formed within said transmission housing, and wherein said enlarged head portion of said plunger extends into said neutral switch bore with said neutral switch being actuatable by each of said plurality of shift shafts to control range shifts in response to actuation by said plunger. 
 
   
   
     2. The vehicle transmission according to  claim 1  wherein said neutral switch comprises a single switch that is independently actuated by each shift shaft from said plurality of shift shafts. 
   
   
     3. The vehicle transmission according to  claim 1  wherein said plunger is positioned directly between one shift shaft of said plurality of shift shafts and said neutral switch. 
   
   
     4. The vehicle transmission according to  claim 3  including a plurality of switch pins wherein each switch pin is positioned directly between another one of said plurality of shift shafts and said plunger. 
   
   
     5. The vehicle transmission according to  claim 4  wherein said plurality of shift shafts each include a switch profile aligned with at least one of said plunger and said plurality of switch pins. 
   
   
     6. The vehicle transmission according to  claim 5  wherein said plurality of shift shafts are each defined by a maximum outer dimension and wherein said switch profile defines a shaft portion having a dimension that is smaller than said maximum outer dimension. 
   
   
     7. A vehicle transmission comprising:
 a transmission housing; 
 a plurality of shift shafts disposed within said transmission housing with each shift shaft being movable along an axis; 
 a plunger adapted for independent actuation by each of said plurality of shift shafts, said plunger comprising a single-piece component having an enlarged head portion that directly transitions into a reduced body portion, and wherein said reduced body portion comprises a pin body that extends from said enlarged head portion to a distal end to define a length of said plunger that is greater than a width of said plunger; 
 a neutral switch aligned with said enlarged head portion, said neutral switch being actuatable by each of said plurality of shift shafts to control range shifts in response to actuation by said plunger, and wherein said plunger is positioned directly between one shift shaft of said plurality of shift shafts and said neutral switch, and wherein said pin body extends outwardly from said enlarged head portion to be engageable with said one shift shaft of said plurality of shift shafts; 
 a plurality of switch pins wherein each switch pin is positioned directly between another one of said plurality of shift shafts and said plunger; and 
 a plurality of switch pin engagement surfaces formed on said enlarged head portion wherein each one of said plurality of switch pin engagement surfaces is engageable against a corresponding one of said plurality of switch pins. 
 
   
   
     8. The vehicle transmission according to  claim 1  including first and second switch pins that are engageable with said plunger and wherein said plurality of shifts shafts comprises at least a first shift shaft, a second shift shaft, and a third shift shaft with said first switch pin engaging said first shift shaft, said second switch pin engaging said second shift shaft, and said plunger engaging said third shift shaft. 
   
   
     9. The vehicle transmission according to  claim 8  wherein said first, said second, and said third shift shafts are all generally parallel to each other with said third shift shaft being positioned intermediate said first shift shaft and said second shift shaft. 
   
   
     10. A vehicle transmission comprising:
 a neutral switch; 
 a plunger for selectively activating said neutral switch, said plunger comprising a single-piece component having an enlarged base portion that directly transitions into a reduced body portion; 
 first and second switch pins engageable with said enlarged base portion of said plunger; 
 a first shift shaft movable along a first axis and engageable with said first switch pin; 
 a second shift shaft movable along a second axis and engageable with said second switch pin; 
 a third shift shaft movable along a third axis and being engageable with said reduced body portion of said plunger wherein movement of at least one of said first, said second, and said third shift shafts along a respective one of said first, said second, and said third axes actuates said neutral switch; 
 wherein said reduced body portion of said plunger comprises a pin body extending outwardly from said enlarged base portion toward said third shift shaft to define a plunger length that is greater than a plunger width; and 
 first and second switch pin engagement surfaces formed as tapered surfaces on said enlarged base portion wherein said first switch pin engagement surface is engageable with said first switch pin and said second switch pin engagement surface is engageable with said second switch pin. 
 
   
   
     11. The vehicle transmission according to  claim 10  wherein said third shift shaft is intermediate said first and said second shift shafts with said first axis, said second axis, and said third axis being parallel to each other, and wherein said first switch pin extends transversely relative to said first axis, said second switch pin extends transversely relative to said second axis, and said plunger extends transversely relative to said third axis. 
   
   
     12. The vehicle transmission according to  claim 10  wherein said first shift shaft has a first switch profile aligned with said first switch pin, said second shift shaft has a second switch profile aligned with said second switch pin, and said third shift shaft has a third switch profile aligned with said plunger and wherein movement of said first switch pin along said first switch profile, movement of said second switch pin along said second switch profile, and movement of said plunger along said third switch profile results in axial movement of said plunger against said neutral switch. 
   
   
     13. The vehicle transmission according to  claim 12  wherein said first shift shaft is substantially defined by a generally constant first shaft dimension and wherein said first switch profile is defined by a first switch pin dimension that is different than said first shaft dimension; said second shift shaft is substantially defined by a generally constant second shaft dimension and wherein said second switch profile is defined by a second switch pin dimension that is different than said second shaft dimension; and said third shift shaft is substantially defined by a generally constant third shaft dimension and wherein said third switch profile is defined by a third switch pin dimension that is different than said third shaft dimension. 
   
   
     14. A method of controlling vehicle transmission range shifts using a common neutral switch comprising the steps of:
 (a) providing a plurality of shift shafts each movable along a respective axis and a plunger comprising a single-piece component having an enlarged base portion that directly transitions into a reduced body portion; 
 (b) positioning a neutral switch within a neutral switch bore formed within a transmission housing such that the enlarged base portion of the plunger extends into the neutral switch bore; 
 (c) actuating the neutral switch via the plunger in response to movement of one of the plurality of shift shafts along one axis; and 
 (d) moving the plunger via a switch pin to actuate the neutral switch in response to movement of another one of the plurality of shift shafts. 
 
   
   
     15. The method according to  claim 14  wherein the plurality of shift shafts includes at least a first shift shaft, a second shift shaft, and a third shift shaft; and including positioning a first switch pin between the plunger and the first shift shaft, positioning a second switch pin between the plunger and the second shift shaft, and positioning the plunger between the neutral switch and the third switch shaft, and wherein step (c) includes moving the plunger in response to movement of the third shift shaft along one axis and step (d) includes independently moving the plunger with at least one of the first and second switch pins in response to respective movement of at least one of the first and second shift shafts along another axis. 
   
   
     16. The method according to  claim 15  including forming a first variable profile on the first shift shaft and aligning the first switch pin for engagement with the first variable profile; forming a second variable profile on the second shift shaft and aligning the second switch pin for engagement with the second variable profile; and forming a third variable profile on the third shift shaft and aligning the plunger for engagement with the third variable profile. 
   
   
     17. The vehicle transmission according to  claim 4  wherein said enlarged head portion includes a first switch pin engagement surface to directly engage a first switch pin and a second switch pin engagement surface to directly engage a second switch pin, and wherein said reduced body portion of said plunger directly engages one shift shaft. 
   
   
     18. The vehicle transmission according to  claim 17  wherein said first and said second switch pin engagement surfaces comprise tapered surfaces. 
   
   
     19. A vehicle transmission comprising:
 a neutral switch received within a neutral switch bore formed within a transmission housing; 
 a plunger for selectively activating said neutral switch, said plunger comprising a single-piece component having an enlarged base portion that directly transitions into a reduced body portion, and wherein said enlarged base portion of said plunger extends into said neutral switch bore; 
 first and second switch pins engageable with said enlarged base portion of said plunger; 
 a first shift shaft movable alone a first axis and engageable with said first switch pin; 
 a second shift shaft movable along a second axis and engageable with said second switch pin; and 
 a third shift shaft movable along a third axis and being engageable with said reduced body portion of said plunger wherein movement of at least one of said first, said second, and said third shift shafts along a respective one of said first, said second, and said third axes actuates said neutral switch. 
 
   
   
     20. A method of controlling vehicle transmission range shifts using a common neutral switch comprising the steps of:
 (a) providing a plurality of shift shafts each movable alone a respective axis and a plunger comprising a single-piece component having an enlarged base portion that directly transitions into a reduced body portion, and wherein the plunger defines an axis that extends along a length of the plunger from the enlarged base portion to the reduced body portion, the length of the plunger being greater than a width of the plunger; 
 (b) forming a first switch pin engagement surface on the enlarged base portion to directly engage a first switch pin, forming a. second switch pin engagement surface on the enlarged base portion to directly engage a second switch pin, forming the reduced body portion of the plunger as a pin body that directly engages one shift shaft, and moving the plunger along the axis in response to at least one of the first switch pin actuating the first switch pin engagement surface, the second switch pin actuating the second switch pin engagement surface, or the pin body being actuated by the one shift shaft; 
 (c) actuating a neutral switch via the plunger in response to movement of one of the plurality of shift shafts along one axis; and 
 (d) moving the plunger via one of the first and second switch pins to actuate the neutral switch in response to movement of another one of the plurality of shift shafts.